JPH04128734A - Overhead projector - Google Patents

Abstract

PURPOSE:To easily exchange a light source and to prevent the infiltration of dust and the damage of other equipments caused by the heat of the light source by providing an opening/closing part for exchanging the light source 1, which has size so as to take out the light source of a light source part provided on the bottom part of a main body. CONSTITUTION:The light source part 30 is arranged in the vicinity of the bottom part 20 of the main body 10. On the other hand, a door 25 as the opening/ closing part is on the bottom part 20 of the main body 10 and of a size to take out a lamp 22 as the light source of the light source part 30. When the lamp 22 is in a bad condition or the filament of the lamp is burst, the door 25 of the bottom part 20 is opened, then the lamp 22 is taken out. Therefore, an operator can exchange the light source 22 without touching the equipments inside the heated main body 10. Thus, the exchange of the light source is stabilized and facilitated, and the damage of other equipments caused by the heat of the light source and the infiltration of the dust are prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] This invention relates to improvements in overhead projectors.

[Prior art] Conventional overhead projector (OHP) shown in Fig. 6
Now, a document is placed on a document table 1, light from a light source is passed through the document, the light is passed through a projection lens 2, reflected by a mirror 3, and projected onto a screen surface.

The document table 1 is located on the upper part of the main body 4, and the light source is arranged inside the main body 4. When this light source malfunctions or burns out, the operator can open the door 5 provided on the side of the main body 4, open the lamp house 6, take out the light source, and replace it with a new light source. Exchange.

Further, in the conventional OHP shown in FIG. 7, the document table 1 is removed upward from the main body 4, and the operator puts his/her hand in from above to open the landing slot 6, take out the light source, and replace it with a new light source.

[Problems to be Solved by the Invention] However, in the conventional example shown in FIG. 6, since the light source is located in the center of the main body 4, the distance from the door 5 to the light source is large.
The operator's hands are likely to touch the various devices inside the main body 4 that are heated by the light source, which is thermally and electrically dangerous. It is also difficult to locate the light source. This makes it difficult to replace. Furthermore, there is a risk of forgetting to close the lamp house 6, and there is a risk that the equipment inside, such as a Fresnel lens, may be damaged by the heat from the light source.

On the other hand, in the conventional example shown in FIG. 7, the operator's hands touch the equipment inside the main body 4, which is thermally and electrically dangerous. Not only this, but since the original platen 1 is removed, the opening is large, making it easy for dust to get inside.

[Object of the Invention] According to the present invention, the light source can be replaced safely and easily, and the intrusion of dust can be prevented, and after the replacement, full-scale equipment will not be adversely affected by the heat of the light source. It is intended to provide an overhead projector.

[Summary of the Invention] The gist of the present invention is an over-rad projector as set forth in the claims.

[Means to solve the problem] Please refer to FIGS. 1 and 2.

The light source section 30 is arranged near the bottom section 20 of the main body 10 of the overhead projector. Door 2 as an opening/closing part
5 is located at the bottom 20 of the main body 10 and is large enough to allow the lamp 22, which is the light source of the light source section 30, to be taken out.

Further, as shown in FIG. 4, a reflecting mirror 24 for reflecting light from the lamp 22 is installed near the door 22.
It is preferable to provide it at 5.

[Function] When the lamp 22 is malfunctioning or burnt out, the door 25 on the bottom part 20 is opened and the lamp 22 is taken out.

[Example] Please refer to FIGS. 1 and 2.

The Overherad projector is of an autofocus type.

The main body 10 is provided with an arm 11, and the arm 11 has a head portion 12 on its upper part. The main body 10 has a power cord 13
, a handle 14, a stage glass 15 serving as a document table, a transparent zoom stage 16, an operation panel 26, and the like.

The head section 12 has a mirror 17, a projection lens 18, and a focus adjustment dial 19.

The projection lens 18 is focused by this focus adjustment dial 19.

The optical system shown in FIG. 3 includes a Fresnel lens 21, a lamp 22, a heat shielding filter 23, a reflecting mirror 24, and a front light source 30 in the main body 10. The heat filter 23 is the lamp 22
This is a transparent filter that prevents heat from being transmitted to the Fresnel lens 21 side.

The reflecting mirror 24 reflects the light from the lamp 22, as shown in FIG. 4, and is fixed to the inner surface of the door 25. The door 25 is hinged at the center of the bottom 20 of the main body 10, as shown in FIG. The door 25 opens when the lamp change lever 33 shown in FIG. 1 is operated. The lamp 22 is placed directly above the door 25 so that it can be easily taken out.

FIG. 5 shows this overhead projector in a closed state. In other words, the head 12 in FIG.
A cover 40 is placed over the main body 10.

Lamp replacement operation In the operating condition shown in FIG. 2, the document 31 is placed on the stage glass 15, the lamp switch is turned on, the lamp 22 is turned on, and this information is projected onto a screen (not shown). .

At this time, if the lamp 22 becomes malfunctioning or burns out, replace the lamp 22 as follows. Turn off the lamp switch on the operation panel 26 and wait until the lamp 22 has cooled down sufficiently. When the cooling fan (not shown) stops, disconnect the power cord 13. Then, fold up the overhead projector as shown in Figure 5. Open the door 25 by operating the lamp change lever 33 shown in FIG. 1, and then hold the handle 14 and place it horizontally as shown in FIG. As shown in FIGS. 3 and 4, the reflector 24 also opens together with the door 25, allowing the lamp 22 to be easily taken out.

Next, take out the lamp 22 shown in FIG. Then, a new lamp 22 is attached to the lamp 22 mounting portion. It can be used by closing the door 25 and unfolding it again as shown in FIG.

However, the present invention is not limited to the above-described embodiments. Instead of the hinged door 25, a sliding door or a removable lid may be used. When the hinge type door 25 is used, since the opening/closing part is provided at the bottom, the main body cannot be installed during use unless this is closed, so the opening/closing part cannot be closed. The door may be structured to close automatically when in use.

[Effects of the Invention] According to the first aspect of the invention, the light source can be replaced electrically and thermally safely and easily without the operator touching the heated equipment inside the main body. Additionally, you can replace the lamp by inserting your hand from the bottom and there is no risk of touching the optical system inside the main body, ensuring the accuracy of the optical system. There is no need to close the lamp house like in the past, and other equipment will not be damaged by the heat of the light source. Also, there is no possibility of dirt getting in.

According to the second aspect of the invention, the reflecting mirror can be removed from the light source simply by opening the opening/closing part, making it easier to replace the light source.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing an embodiment of the autofocus projector of the present invention, Fig. 2 is a diagram showing the projector in a folded and laid-down state, Fig. 3 is a side view showing the optical system, and Fig. 4 is a diagram showing an embodiment of the autofocus projector of the present invention. FIG. 5 is a perspective view showing the door and lamp, FIG. 5 is a view showing the projector in a closed state, and FIGS. 6 and 7 are views showing a conventional projector. 10...Body 12...Head 22...Lamp 25...Door agent Patent attorney 1) Toru Bebe Fi
g, 2 Fig, 3

Claims (1)

[Claims] 1. In an overhead projector that projects a document using light from a light source built into the main body, the bottom (2) of the main body (10) of the overhead projector
0), and the bottom (2) of the main body (10) of the overhead projector.
1. An overhead projector comprising: a light source replacement opening/closing part (25) of a size that allows the light source (22) of the light source part (30) provided in the light source part (30) to be taken out; 2. The overhead projector according to claim 1, further comprising a reflecting mirror (24) near the light source (22) for reflecting future light;
24) is attached to the opening/closing part (25).